I get what you're saying, but while Pacquiao did have decisions go his way he also had some taken from him (Bradley, Horn), while Canelo's history is questionable decisions and scorecards all in his favor. On the PEDs, one of the two failed tests.
The decisions taken away from Pac where years later at an advanced age, it might go that way for Nelo yet. As for the PEDs, depends if you believe the tainted beef or not I guess. I personally struggle to believe any top level athlete is clean.
Are you asking how a 30 year old man, who has spent the past 10 years training like an elite athlete is stronger than his 20 year old self?
I don't have to explain anything, it's not me who's in charge of these things. They credited him with it after he beat Bradley in the third fight.
Most men are at their strongest physically around age 30, give or take a few years ... Then they decline.
How did he get so strong? Same way Vinnie Pazienza went from a 135 pounder to a hulking 168, steroids. The same way Holyfield went from a slim 175 to a strong heavyweight able to battle Bowe. Same way Manny went from 122 to knocking out 147 pounders, Steroids. Now he does have a strong work ethic though.